The present invention relates to a synthetic resin fastener (hereinafter, referred to simply as "fastener") which is to be used in fixing a first member having a first attaching hole formed therein to a second member having a second attaching hole formed therein, and more particularly, to a fastener which is suitable for fixing a rubber weather strip for automobile (first member) to a car body sheet metal (second member).
A synthetic resin fastener has been proposed in Japanese Utility Model Unexamined Publication Nos. 59-20016 and 63-119112 and Japanese Patent Unexamined Publication No. 4-296209.
As shown in FIG. 1, the conventional fastener comprises a head portion 21 which is to be engaged with a surface-side peripheral edge of a first attaching hole 15 (the edge located on the side from which a fastener is inserted), a seat portion 25 extending from a rear surface of the head portion 21 through a neck portion 23 so as to be brought into engagement with a surface-side peripheral edge of a second attaching hole 19, and an anchor portion 27 extending from a rear surface of the seat portion 25 so as to be brought into engagement with a back-side peripheral edge of the second attaching hole 19. The anchor portion 27 comprises a pillar portion 29 extending from the rear surface of the seat portion 25 and a pair of engaging elastic am portions 33 each extending from the tip end portion of the pillar portion 29 towards the seat portion 23 and having an engaging pawl portion 31 formed at the tip end thereof.
When fixing a weather strip to sheet metal 13 of a car body, it has been customary that the first attaching hole 15 is formed in the weather strip 11, the fastener 17 is attached to the weather strip 11 through the first attaching hole 15, and then the fastener 17 is inserted into the second attaching hole 19 formed in the car body sheet metal 13 (see FIGS. 1.about.2).
Recently, changes have been made in the plate thickness of the structure of the car body sheet metal (double-ply flange, triple-ply flange and so on) and, further, in order to improve productivity, the allowable tolerances of plate thickness have increased. For this reason, when using a fastener having the above-described construction, it is necessary to prepare two or more kinds of fasteners which have engaging elastic arm portions 33 corresponding to various plate thicknesses. The reason for requiring different kinds of fasteners is that, when applying a synthetic resin fastener 17 which is suitable for car body sheet metal having a large thickness 13 as shown in FIG. 1 in a car body sheet metal having a small thickness 13A as shown in FIG. 2, the engaging pawl portion 31 of the engaging elastic arm portion 33 cannot be engaged with the back surface surrounding the second attaching hole 19, resulting in the occurrence of play.
Further, it is not advisable to use two or more kinds of fasteners in fixing the same weather strip due to the increased risk of misassembly.
In view of the above-described problems, an object of the present invention is to provide a synthetic resin fastener which is adapted to be cooperable with a second member having a variation in plate thickness.